World Gem Foundation
Coloured Gemstones

Coloured Gemstones Course

Prerequisites

None

Lessons

Twenty-Nine

Course Objective

This course concentrates on the twenty-six most common groups, species and varieties of coloured gemstones giving a comprehensive overview of their physical and optical properties, their unique identifying features, and how they are graded.

Topics Covered Include

Physical properties, geology, localities, crystal system, chemical composition and causes of colour, varieties, absorption spectra, pleochroism, inclusions, fluorescence, gem identification, synthesis, common treatments and enhancements, and care guidelines. Gemstones covered in this course include corundum (rubies and sapphires), beryl (emeralds, aquamarines and other precious beryl), chrysoberyl (alexandrite and other chrysoberyl), spinel, zircon, topaz, tourmaline, peridot, quartz, garnet, tanzanite, lapis lazuli, turquoise, spodumene (kunzite and hiddenite), feldspars, iolite, andalusite, diopside, apatite, and organic gems (pearls, coral, jet, ivory, and amber).

Coloured Gemstone Grading

You will learn how to accurately describe colour based on hue, tone and saturation, the various colour grading systems currently used by professionals, the clarity classification of gemstones based on their geological environments, how cut is assessed, opal, jadeite and pearl grading, and how weight is assessed in a 'mounted' coloured gemstone.